Quantitative Structure Activity Relationship Studies
Quantitative structure activity relationship (QSAR) is a technique that quantifies the relationship between structural and biological properties.
A QSAR can be expressed in its most general form by
Biological activity=f (physicochemical and/or structural parameters)
The physicochemical descriptors include parameters that account for hydrophobicity, topology, electronic properties and steric effects, and are determined empirically by computational methods. Activities used in QSAR include chemical measurements and biological assays.Researchers have attempted for many years to develop drugs based on QSAR. An example some compounds were interest for their anti-tumour activity, but they also were mutagenic. QSAR was applied to understand how the structure might be modified to reduce the mutagenicity without significantly decreasing the anti-tumour activity.
In a quantitative activity relationship study, the antileishmanial activity of substituted pyrimidine and pyrazolo pyrimidine analogues was determined using physicochemical and steric descriptions (hydrophobicity, molar refractivity, Suptons resonance,Verloop’s steric parameters, van der Waals volumes of the substituent groups) of the varying substituents. The study of pyrimidine analogues indicated the necessity of having unsubstituted pyrimidine for antileishmanial activity. A linear multiple regression analysis with least square method was applied in developing correlation.
